Anisotropic Turbulence and Rossby Waves in an Easterly Jet: An Experimental Study

Authors

Boris Galperin, University of South FloridaFollow
Jesse Hoemann, University of South Florida
Stefania Espa, Sapienza Università di Roma
Gabriella Di Nitto, Sapienza Università di Roma

Document Type

Article

Publication Date

2014

Keywords

zonal jets, planetary macroturbulence, Thorpe scale

Digital Object Identifier (DOI)

https://doi.org/10.1002/2014GL060767

Abstract

A westward propagating jet is investigated experimentally. The focus is on complex interaction between anisotropic turbulence with inverse energy cascade and Rossby waves. The energy spectrum is highly anisotropic. To diagnose turbulence characteristics, we explore the analogy between turbulent overturns in stably stratified and quasi-geostrophic flows and develop a novel method based upon the monotonizing of potential vorticity (PV). The RMS displacement from the monotonic PV profile yields a length scale, L_M, analogous to the Thorpe's scale used in flows with stable stratification. As the Thorpe scale is proportional to the Ozmidov scale, the scale L_M is proportional to the scale L_β at which the time scales of turbulent overturns and Rossby waves are approximately equal. The relationship between L_M and L_β is established here for the first time. The method of PV monotonizing offers a simple and powerful tool for diagnosing geophysical and planetary macroturbulence.

Rights Information

Terms of use for work posted in Scholar Commons.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Geophysical Research Letters, v. 41, issue 17, p. 6237-6243

©2014. American Geophysical Union. All Rights Reserved.

Scholar Commons Citation

Galperin, Boris; Hoemann, Jesse; Espa, Stefania; and Nitto, Gabriella Di, "Anisotropic Turbulence and Rossby Waves in an Easterly Jet: An Experimental Study" (2014). Marine Science Faculty Publications. 1496.
https://digitalcommons.usf.edu/msc_facpub/1496